Closure arrangement



April 23, 1940.

K. H. M AY CLOSURE ARRANGEMENT Original Filed Feb. 11, 19s? 3 Sheets-Sheet 1 INVENTQR. MI

A TTORNEYS.

April 23, 1940. K, H. MacKAY 2,198,121

" CLOSURE ARRANGEMENT Original Filed Feb. 11, 19s? a Sheets-Shet 2 INVENTOR.

A TTORNEYS.

syf MW Q /1114 April 23, 1940.

K. H. M KAY CLOSURE ARRANGEMENT Original Filed Feb. 11, 1937 3 Sheets-Sheet 3 & & g 125 g W I N V EN TOR. 1 1M ziw z/a A TTORNEYS.

Patented Apr. 23, 1940 UNITED STATES CLOSURE ARRANGEMENT Kenneth H. MacKay, Ocala, Fla.

Continuation of application Serial No. 125,337,. February 11, 1937. This application February 2, 1938, Serial No. 188,343

15 Claims.

This invention relates to closure arrangements, and particularly to such arrangements whereby an effective seal may be provided between relatively moving mechanical parts. Such devices may be employed in a widevariety of environments, one example of which is a rotary motor or compressor of the type disclosed in my copending application Serial No. 220,689, filed July 22, 1938. Such a machine is provided with slide l0 valves which may be constructed to operate in the manner taught by this invention. Such a motor or compressor is also provided with cam operated abutments movable into and out of the path of rotary vanes to cooperate therewith in providing expansible or contractible fluid-containing chambers, and these abutments may also be constructed and arranged to operate in the manner taught by the present invention.

In general, however, the principles of this invention are applicable to movable closures such as valves, pistons, plungers, or the like, where it is desired to afford an efiective fluid-tight seal between the surface of the closure and the surface of a cooperating member.

To permit these desirable results, the closure assembly may afford a fluid-containing chamber with a wall portion thereof provided by the movable closure member, suitable hydraulic means being provided to force fluid under pressure into the chamber thereby to cause the movable wall portion firmly to be pressed against a cooperating guide surface, thereby afiording an effective fluid-tight seal for the valve, plunger, movable abutment or the like. Such a hydraulic arrange- 35 ment may also be arranged to cause the actuation of the closure. This actuation may be effected periodically against the action of a suitable return spring or springs. If desired, the fluid which causes movement of the wall portion of the closure may also be circulated so that the closure is cooled by the fluid. In certain cases, it may be desirable to have the wall portion: move relative to the closure under the control of fluid in order to ensure a firmengagement of parts, as the firm engagement of the head portion of an abutment and a complementary recess of the general type disclosed in my above-identified application or, if preferred, such a head portion or the like may be given an accelerated movement compared -to the remainder of the abutment member, so that the efiect is realized, which would be obtained if a more steeply shaped cam were provided for actuating the abutment member.

In one typical embodiment of the invention, a

hollow slide valve may be provided which is hydraulically actuated by fluid which is also effece tive in tending to press the thin walls of the slide valve firmly against the channel in which the valve is slidable thereby to afiord an efiective seal. Such an arrangement may also be provided so that oil is circulated through the slide valve between each period of operation thereby effectively to cool the valve. Another arrangement involves the provision of thin-walled extensible chambers on the heads of abutment members which are pressed firmly against the channels in which the abutments slide, while the heads of the abutment members may be movable relativeto the remainder thereof so that an unusually firm and efiective seal is afforded. A somewhat similar arrangement may be provided to cause the acceleration of the head of the member relative to the body portion thereof, thus giving a degree of acceleration to the head of the abutment member which would be afiorded were a relatively steep cam employedv to actuate the abutment member.

In the accompanying drawings:

Fig. 1 is a vertical sectional view of a slide valve assembly showing hydraulic means for actuating a valve and for pressing the surface of the valve firmly against its channel when the valve is actuated and for cooling the valve; V

,Fig. 2 is a vertical section of part of an engine cylinder head structure having incorporated therein valve actuating means embodying my invention. In this showing the .cylinder head structure is that ofa conventional reciprocating internal combustion engine;

Fig. 3 is a vertical sectionalview of an abutment assembly such as is provided in my aboveidentified copending application, the assembly, however, being modified in accordance with the I, principles of the present invention;

Fig. 4 is a section indicated by line 4-4 of Fig. 3; Y I

Fig. 5 is a view similar to Fig. 3, but showing certain parts of the assembly in a somewhat different relative position;

Fig. 6 is an enlarged sectional detail of a portion of the assembly shown in Figs. 3 and 5; s

Fig. 7 is an isometric View of a retaining member provided on the abutment shown in Figs. 50 3 and 5;

Fig. 8 is a view similar to Fig. 3, but showing an optional arrangement of an abutment assembly with means provided to accelerate the abutment head at the end of its path; .and

Fig. 9 is a view of an optional arrangement of an abutment assembly.

In the accompanying drawings, certain closure arrangements are illustrated which may be em ployed in a motor or compressor of the character shown in my above-identified application, but it is to be understood that this disclosure is but an example of various closures which may operate in accordance with the principles of this invention to provide the same general advantages.

Fig. 1 shows a portion of an. annular casing l on which a slide valve 2 is mounted to reciprocate in a channel 3 provided by an extension i of the annular casing. This valve is slidable to cover or uncover suitable ports 5 through which fluid, such as a gaseous charge, may pass. Compression springs I are provided at each side of the port yieldably to urge the valve toward its open position, and when these springs are fully compressed, they limit the movement of the valve away from its open position. When the valve has moved to its closed position, it extends across the ports 5 so that the movement of the gaseous charge through the ports is prevented,

As shown, the valve 2 may be in the form of a box-like member of relativelythin metal having an open end which is slidably received in suitable recesses defined by a sealing member lil which fits within the end of the box-like valve mem-' her. The sealing member H) is provided with an open end communicating with a passage l2 that in turn communicates with a plunger chamber l3 in the annular casing I. A plunger M is slidably mounted in this chamber. being provided with an end portion l5 which affords a follower for an actuating cam It, the movement of the plunger It by the cam l5 being opposed by a compression spring H which is disposed eccentrically about a spindle l8 extending from the plunger into the chamber !3 and having an end portion slidable in a collar 23 at the end of the chamber.

It is to be understood that when the cam l6 actuates the plunger I4, hydraulic fluid is forced from the chamber [3 through the passage !2 into the interior of the box-like guide It and the hollow valve 2, thus causing the valve to slide outwardly to cover the ports 5 against the action of the springs 1. Furthermore, since the slide valve 2 is formed of thin metal, the hydraulic pressure thus imposed tends to press the surfaces of the valve more firmly against the walls of the channel 3 in which the valve is slidable, thereby assuring an effective fluid-tight seal when the slide valve closes the ports 5.

A second radially disposed plunger 35 is slidably mounted in the casing i, being movable by a cam 3| against the action of a compression spring 32. This plunger is provided with a portion 33 of reduced diameter which, when the plunger moves outwardly, registers with a passage 29 communicating with the open end of the guide l0 and the interior of the valve 2 and with an outlet duct 34 from which oil may drain to a suitable sump (not shown).

The plunger 38 is also provided with a second annular groove 3'! which communicates with an inlet duct 38 through which oil is supplied under pressure, as, for example, from a suitable conventional oil pump or other means, not shown, which also may supply oil under pressure for lubricating the motor or the like. The groove 3'! also communicates with a supply passage Ml through which oil received from the duct 37 may pass to the chamber l3 and thence to the interior of the guide It and the slide valve 2, filling the passages I2 and 29 which communicate therewith.

In order to prevent the passage of the incoming oil directly from chamber $3 to the outlet duct 36, a suitable deflector 43 may project radially from the casing, this deflector having a lower upwardly inclined surface to prevent the pocketing of air. In order to permit surplus oil to be emitted from the chamber and to permit air to pass out from the chamber, the spindle i8 provided with an orifice 55 at the top of the chamber which bleeds the air from the chamber together with excess oil.

In the operation of a Valve of this character, it is to be understood that the cams Hi and 3| are fixed to the main shaft of the motor or com press-or and that these cams respectively engage the plungers It and 3% in succession. When the cam 3| engages the plunger 38, the latter is moved radially outward so that the groove 3'! first causes the passages 38 and M) to communicate with each other so that there is a tendency for the pressure from the oil supply line from the pump (not shown) to force oil through the passage 45 into the chamber l3. Since, however, this chamber may be normally full of oil, there is little tendency toward movement of the oil through these passages until the continued movement of the plunger 30 causes the passage 29 to communicate with the outlet 34. Thereupon the oil within the hollow valve 2 and the guide I!) may drain through the passage 34 to the sump. This oil may be relatively warm and is replaced by cooler oil entering the chamber through passage 40.

The incoming oil is prevented by the deflector 43 from passing directly to the outlet 34 and thence to the sump, so that circulation of oil takes place in the hollow valve 2 and the latter is effectively cooled by the incoming oil, which replaces a substantial portion of the oil previously contained in the chamber. 'I'hereupon as the plunger 30 returns to its normal position under the influence of spring 32, the passage to the outlet 34 is first closed, while oil continues to enter through the duct 48 so that substantial filling of the chamber is assured. Since, however, the orifice 5B is at the upper part of the chamber, collected air will pass out of this orifice, while surplus oil may also pass out of the chamber in this manner.

After the plunger 30 has thus been actuated, the valve 2, which is in its open position, is filled with relatively cool oil and the movement of the cam-shaft continues until the cam i6 engages the plunger hi, whereupon the orifice 50 moves into the collar 23 so that the emission of fluid through the orifice is prevented as the plunger continues to move inwardly, forcing the oil under pressure into the valve chamber and causing the latter to move radially outwardly against the action of springs 1. As this occurs and particularly at the end of such movement, the pressure within the hollow slide valve 2 is materially increased so that the surfaces thereof, and particularly the flat side surfaces, are pressed more firmly against the sides of the channel in which the valve 2 slides. Y

The valve 2 is thus held in its closed position until the cam l6 permits the spring ll to return the plunger M to its normal position. The parts then remain in this position until the plunger 30 is again actuated to permit warm oil to be released from the valve chamber and cooler oil to replace the same.

- It is evident that this arrangement may be employed to permit the hydraulic actuation of a closure, such as a slide valve, to permit the concomitant cooling of the valve, and to cause the distention of the thin-walled valve member so that its outer surfaces are more firmly pressed against the cooperating surfaces of the guide channel. I

Fig. 3 illustrates an abutment member, designated generally by numeral 633, which is actuable by a cam El engaging a follower 62 secured to a spindle 63. A coil compression spring 64 may be arranged to press the follower 62 against the cam and to return the abutment member to its normal position after the cam has passed out of engagement with the follower. Such an abutment member, as shown in my aboveidentified application, may be movable into a channel 65 .tocooperate with blades rotatable in that channel in defining fluid-containing chambers. Pref erably, as shown, such an abutment member is provided with a beveled surface defining one side of a bluntly pointed end portion which is engageable in a complementary recess 51 on the, inner wall of the channel 65.

In accordance with the present invention, the abutment member may comprise an outer plate 68 which is fixed to the spindle B3 and an inner head 66 which is slightly movable relative to the spindle and the plate 68. For this purpose an extension 63 of the spindle, which is of reduced diameter, may have a Sliding engagement with a suitable bore in the head portion 66, while a light compression spring 10 is disposed between a shoulder on the spindle 63 and a shoulder on the head portion tending to urge the head portion away from the plate 68. This relative movement, however, is limited bya diametric pin H extending through the spindle 63 so that only limited movement of the parts can take place.

In accordance with this invention, the abutment member 60 is slidable in a suitable channel 74 disposed outwardly of the channel 65, and when the abutment member is in its outermost position, the space or chamber 15 between the plate 68 and the head 69 communicates with an oil supply passage l8 through which oil may be supplied 'under pressure from a conventional lubricating oil pump, not shown. Accordingly this chamber is filed with oil when the abutment B0 is retracted. Thereupon, when the cam SI advances the abutment so that it extends across the channel 65, the oil in the chamber 15 is sub-- jected to pressure and the spring 18 is slightly compressed. Thus the head 69 is firmly pressed against the recess 61 in the inner wall of the channel 65.

Furthermore, the chamber 15 communicates through suitable passages in the head 89 (Fig. 6) with thin-walled chambers or channels 8! which extend along three straight surfaces of the abutment member, so that these channels are filled with the hydraulic fluid. Accordingly, when the pressure is increased due to the movement of the outer plate 68 toward the head 69 and particularly at the end of such movement, the outer walls of channels 8| are distended outwardly. A retaining member of the form shown in Fig. '7 may extend about the outer surfaces of these channels, this member being provided with an inturned flange 86 which extends about the end of the channel at one end of the abutment member and being provided with an outturned flange 87 at the opposite end of the abutment member which slides in a suitable recessed portion of the guiding frame. As shown, the upper part of the retaining member 85 may be provided with relatively deep vertical slits 88 to permit the slight distention of this portion of the retaining member, as the channels 8| are distended under the hydraulic pressure. Accordingly, the outer surface of the retaining member is firmly pressed against the complementary surfaces ofthe guide passage 74 for the abutment member. Thus an effective fluid-tight seal may be provided between these parts.

When the abutment member moves outwardly, the plate 68 moves slightly away from the head 69 to relieve the hydraulic pressure, whereupon the pin H is effective in causing the head to move with the plate 68 and spindle 63 as these parts continue their outward movement. As this movement is terminated, the chamber 15 again communicates with the passage 18 so that any oil which has leaked out of the chamber 15 may be replenished, whereupon the operating cycle may be repeated.

Openings 88 preferably may inner ends of the channels 8| to permit slight leakage of fluid from these channels when the fluid is subjected to increased pressure, due to the movement of plate 68 toward head 66. Thus any pocketed air may be vented for the fluidcontaining'space and oil may be supplied to the wall of channel 18 to aid in lubricating the same.

Referring to Fig. 2 which shows the hydraulic closure of my invention in a reciprocating internal combustion engine: Cylinder head struc ture 28! is shown having a hollow sliding valve 202 mounted therein and maintained in open position with respect to passage 225 by the compression spring 283, the said cylinder head structure including an upper valve actuator structure 284 chambered to provide a valve actuator chamber 2855 tothe interior of which the open end of the valve 202 tended to contain a hydraulic fluid, such as' oil, which acts as the valve 202 from an actuator plunger 286, one end of which plunger is also exposed to the interior of said actuator chamber 285 and the other end is'pressed against a cam 20'! by a plunger spring 288 so that the said plunger wil follow the contour of the said cam.

289 is a fluid manifold preferably supplied with oil under pressure, and 2H) is a check valve adapted to open from the said manifold into the actuator chamber 205 when pressure in the manifold 289 exceeds pressure in the actuator chamber to an extent sufficient to overcome the resistance of the check valve spring 2H. The check valve is indicated as being housed in a be provided in the municating with the actuator chamber to permit the required flow from the manifold to the actuator chamber when the check valve is open. This casing is held in position on suitably provided seats by the plug M5 in the top of the actuator structure. I

The actuator structure 204 is also shown as housing a further plunger 216 which forms a relief valve as will having its lower end also 287, by reason of theaction spring 2H confined between I and a plug H8 in the upper end of the said actuator structure 204, the said plunger 216 being so arranged radially of the cam that its operation alternates with thatof the plunger 206.

of the relief valve is exposed. This chamber is ina means of transmitting motion to be explained, this plunger bearing on the cam The plunger H6 is tubular and has an outlet passage at its lower end and an inlet passage 220 towards its upper end, which inlet passage opens from an annular groove 22| in the said plunger 2H5 adapted to register with a relief port 222 of the actuator chamber 265 when the said plunger 2H5 is raised to a sufiicient extent by the lobe of the cam 201. This relief port 222 opens from a high point or region of air accumulation in the actuator chamber 265.

Arranged within the tubular plunger 24s is a spring pressed check valve 223 permitting outward or downward flow only through the said plunger.

As previously explained, rotation of the cam 20! effects intermittent lifting of the plunger 29% and the consequent operation of the valve 262, and during such time as the valve 292 is closed and the plunger 2% in a position other than dwelling on the base circle of the cam, fluid in the actuator chamber 205 is subjected to considerable pressure so that there is no tendency of the check valve 2 l i) to open. During this pressure period the plunger 2l6 dwells on the base circle of the cam so that the annular groove 22| thereof and the relief port 222 of the actuator chamber do not register, the hydraulic fluid, therefore, being effectively confined in the actuator chamber.

After the lobe of the cam passes beyond the actuator plunger 206 in whichever direction the said cam may rotate, it eventually raises the plunger 2H5 until the annular groove 22! thereof coincides with the relief port 222 of the actuator chamber, but at this time it will be understood the plunger 295 again dwells on the base circle of the cam, and the valve 292 is open so that there is then no pressure exerted on the fluid in the actuator chamber. As a consequence, slight pressure of fluid in the manifold 269 will lift the check valve 210 and result in flow taking place through the actuator chamber and therefrom by way of the relief port 222 through the hollow interior of the plunger 2V5 and the outlet passage 2 l9. The check vale 223 offers but little resistance to this flow which is easily overcome.

The said flow of oil through the actuator chamber during the period of valve inaction is effective both to scavenge air from the said chamber and to ensure a replenishing of oil therein to compen sate for any loss by leakage or otherwise, whereby a complete filling of the chamber with oil prior to the ensuing valve actuating movement of the plunger 206 is ensured as required to ensure proper translation of plunger movement into valve movement.

The valve 292 may be of rectangular box-like form having an open end slidably fitting within the guide 224, it being evident that when the valve 202 is moved to its closed position against the action of spring 203, the thin walls of the hollow valve are distended, thereby to afiord an effective fluid-tight seal. While the slide valves illustrated in Figs. 1 and 2 are of rectangular box-like form, it is evident that the shapes of these valves may be varied as desired. Thus, for example, such valves might be provided with curved or arcuate cross sections, or they might have cylindrical cross sections.

Fig. 8 illustrates an abutment assembly with the parts arranged similarly to those shown in Figs. 3 to 7, such parts being designated by similar refer ence numerals. However, in accordance with this embodiment of the invention, a slot 99 communicates with the chamber 15 and an oil duct 18 is arranged to supply oil through the passage 99 to the chamber 15. This duct 18 preferably communicates with a small plunger pump, designated in general by numeral 95, which may receive oil from the oil pressure line of the motor or compressor. This pump 95 may be located at any convenient point remote from the abutment assembly, being provided with the piston 96 which is provided with a rod 91 having a follower 98 engaging an operating cam 99. A spring Hi presses the piston 96 toward the cam 99 so that the follower is held in engagement with the cam. When the piston moves downwardly, oil is admitted to the chamber of the pump through the passage I08. A suitable check valve IM in the passage N38 is provided to prevent the movement of oil from this chamber when the piston 95 moves toward the cylinder head under the action of cam 99. As this occurs a pressure impulse is imparted to the oil contained in the duct 18, the groove 99, and the chamber iii. A check valve 18 permits the flow of oil through the duct 18 to the groove 90 and the chamber 15 as the piston 96 moves upwardly to provide a pressure impulse. The parts are so synchronized that this impulse is provided just as the abutment head approaches the end of its path, so that a movement of the abutment head inwardly toward the channel 65 relative to the spindle $3 and the plate 68 is provided. Accordingly, while the last-named parts are moving inwardly toward channel 65, the movement of the head is i accelerated and the latter recives a total movement similar to that which would be provided if the actuating cam were provided with a steeper.

rise. across the channel 65, while at the same time this head may be provided with the thin-walled sealing channels 8! which are distended in the manner already described with reference to Figs. 2 to 7 inclusive. This movement of the head relative to the remainder of the abutment assembly is yieldably opposed by a compression spring ITO disposed in a recess I65 between the enlarged portion H63 of the spindle G3, and a shoulder provided by the abutment head. Accordingly,

when the pressure within the chamber 15 is released, the head is moved by the spring I10 toward the plate 68.

The pressure within the chamber may be released by means of the piston 96, the side wall portion of which is provided with a recess E33 affording communication between a duct I34 extending from the chamber 75 and a relief duct I34. Thus, as the cam 99 passes out of engagement with the follower 98, the spring I90 moves the piston 96 downwardly so that the pressure in chamber 15 is relieved and the spring i'lii may be effective in moving the abutment head toward the plate t8, this action tending to squeeze some of the oil from the chamber 15. Obviously, this relative movement of the parts of the abutment assembly may occur as the latter is starting its outward movement away from the recess 61. Thus a movement is afforded for the abutment head like that which might be provided were the cam to have a more steeply inclined surface engaging the follower as the abutment moves outwardly.

Fig. 9 shows an optional arrangement of an abutment of the general character illustrated in Fig. 8. Such an abutment may be actuated by a cam El, which engages a follower 32 at the end of a spindle E63. As shown, a compression spring 164 tends to move the abutment out of the channel I65 and to hold the follower 62 against the cam 6|. The abutment includes a plate I68 Thus the head may move more rapidly fixed to the spindle I63 and a head portion I 60 movable on the end of the spindle. For this purpose, the end of the spindle is provided with an enlarged portion I63 which engages the end of I a compression spring I68 in a recessed portion I10 of the head. The spring I68 tends to urge the head I60 toward the plate I68, the part 33 acting as a stop to limit this movement. When the follower is engaged by the cam BI, the abutlfl'ment is moved to the position indicated in dot and dash lines in Fig. 9, so that the bluntly pointed end of the abutment is engaged in the recess I61 in the wall of channel I65. This abutment may be provided with any suitable chamlLbers having distensible wall portions. As shown, a narrow channel I80 is provided in the head I60, this channel having an outer wall provided by a thin plate I85 integral with the body portion of the head.

The space between the plate I68 and the head I60 affords a fluid containing chamber which communicates through a passage I'IB with a chamber in which a plunger I96 is slidably mounted. The plunger I95 is provided with a 25 follower I98, which is engaged by the cam III directly after the cam engages the follower I62. As this occurs, the plunger moves inwardly, compressing the spring IG'I, and causing oil which is supplied through a duct IE8 from any suitable source of supply to be forced outwardly through the check valve I95 and the passage I18 into the space between the plate I68 and the abutment head I66. Thus at the end of the inward path of the abutment assembly, an accelerated motion ""is imparted to the head I69, due to the pressure impulse imposed by the plunger I66. Preferably, as shown, the inlet duct It's for the plunger chamber may be provided with a check valve I 04.

, As the cam GI continues its movement, it endo 'gages a third follower I22 mounted on the end of a plunger I2I having an annular groove 233. This action occurs as the cam passes out of engagement with the follower IE2 and the spring i I 64 tends to return the abutment assembly to *its outermost position shown in full lines. As the plunger I2I is moved inwardly, the annular groove 233 permits the passage 235 to communicate with the relief duct 23 5', thus permitting the oil pressure between the members I58 and 80"I60 to be released, as the spring I'IIl is effective in moving the abutment head I'SIl toward the plate I68.

It is thus evident that the arrangement shown in Fig. 9 affords an assembly whereby the abut- 65 ment, the abutment head, and a relief valve, may

be actuated by a single cam, so that as the abutment moves inwardly, the head I60 has an accelerated motion such as would be afforded were the abutment being actuated by a cam having 60*a. more abrupt rise, and so that as the abutment moves outwardly, the spring I66 is efiective in giving the head I60 an accelerated motion in an outward direction.

v It is evident that the present invention pro- 65 vides closure members which may include movable wall portions that are pressed into firm engagement with the surfaces of. cooperating guide wall portions to afford a fluid-tight seal and that such an action may take place concomitantly with the hydraulic actuation of the closures, if

desired, or that such action may take place while a portion of the closure is being accelerated or decelerated relative to the remainder thereof,

and also that an arrangement of this character 75 may be associated with suitable means period ically to replace the hydraulic fluid to cool the closure.

While devices of this character have been illustrated and are in fact particularly applicable to a motor or a compressor of the type disclosed in my above-identified application, it is to be understood that the principles of the invention may be employed generally with slide and similar forms of closures.

It should be understood that the present disvalves, plungers closure is for the purpose of illustration only movable relative to the opposite wall of the chamber, said wall portion providing an outer surface juxtaposed to a cooperating surface of the other'member, and hydraulic means eifective to cause the relative movement of said members in response to hydraulic pressure and concomitantly to subject the fluid in said chamber to increased pressure to cause movement of said wall portion in the direction of the relative movement of, said members to cause said wall portion to have an accelerated rate of movement relative to the other member.

2. A slide valve assembly comprising a hollow.

fluid-containing valve, a guide structure in which said valve is movable, said structure providing a,

guide extending into and interfitting with the end of said hollow'valve, and means for actuating said valve to slide the same along a path defined by said structure and for distending the valve at the end of its path.

3. An abutment assembly comprising a spindle, a plate fixed to the spindle, a head having a slight movement relative to the spindle, a spring tending to move the head toward the plate, means for actuating and guiding said assembly, and hydraulic means for causing the movement of the head away from the plate as the assembly is being actuated.

4. An abutment assembly comprising a spindle,

a plate fixed to the spindle, a head having a slight movement relative to the spindle, a spring tending to move the head I toward the plate, means for actuating and guiding said assembly, and hydraulic means for causing the movement of the head away from the plate as the assembly is being actuated, said head including a chamber which is hydraulically distended as the head is moved away from the plate.

5. Mechanism. of the class described, compris guiding structure for ing a movable assembly, said assembly defining the path of the same, actuating means directing the assembly along said path, said assembly comprising a body portion and a head portion movable relative thereto, said assembly providing a fluid-containing chamber between said portions, and means to subject the fluid in said chamber to a pressure impulse to cause the head portion to accelerate relative to the body portion as said assembly is moved along its path by the actuating means.

6. Mechanism of the class described, compris ing a slide valve, a guide channel in which said valve is slidable, said valve afiording a hollow thin-walled chamber and having walls distortable under hydraulic pressure, and hydraulic means for periodically sliding the valve in its channel and hydraulically distending the walls of the chamber when said sliding is completed.

'7. Mechanism of the class described, comprising a slide valve, a guide channel in which said valve is slidable, said valve affording a hollow thin-walled chamber and having walls distortable under hydraulic pressure, and hydraulic means for periodically sliding the valve in its channel and hydraulically distending the walls of the chamber, said means including a camactuated plunger movable into a fluid-containing chamber communicating with the chamber within the valve, and means for emitting oil from said chamber and replacing said oil with fresh oil.

8. A closure assembly comprising relatively movable members, said assembly affording a fluidcontaining chamber with a metal wall portion thereof provided by one of said members, said wall portion being capable of distending away from the opposite wall of the chamber and providing an outer surface juxtaposed to a ccoperating surface of the other member, and hydraulic means efiective to cause the relative movement of said members in response to hydraulic pressure and to subject the fluid in said chamber to increased pressure at the end of the relative move ment of said members, thereby to cause outward distending movement of said wall portion and the firm sealing juxtaposition of said cooperating surfaces.

9. A closure assembly comprising a guide, a closure slidably movable in said guide, said ole-- sure affording a fluid-containing chamber with a metal wall portion thereof capable of buckling away from the opposite wall of the chamber, said wall portion providing an outer surface juxtaposed to a cooperating surface of the guide and normally in slidable engagement therewith, and hydraulic means effective to impose pressure upon a body of fluid to effect the movement of the closure in the guide and to subject fluid in said chamber to increased pressure at the end of the movement of said closure thereby to press said wall portion into firm sealing engagement with said cooperating surfaces.

10. A closure assembly comprising relatively movable members, one member of which has a fluid-containing chamber with a wall portion movable substantially perpendicular to the direction of said relative movement, said wall portion providing an outer surface juxtaposed to a cooperating surface of the other member, said relative movement taking place while said juxtaposition continues, means to actuate said fluid-containing member to said relative movement, said actuation means exerting its sliding force principally upon portions of said fluid containing member other than said wall portion, said means also causing said perpendicular movement of said wall portion after said relative movement has been completed.

11. A closure assembly comprising a housing having a conduit therethrough for the transmission of fluid, a valve piece, there being a guide channel in said housing intersecting said conduit innermost position and for laterally distending a portion of the valve piece adjacent said hollowedout portion, said lateral distension taking place after said innermost position is reached, said actuating means exerting its sliding force principally upon portions of said valve other than said.

portions to be distended.

12. A closure assembly comprising a housing having a conduit therein, there being a channel in the housing intersecting with and extending to the opposite side of said conduit, said channel being sealed off at its end away from the conduit, a head adapted to slide in said channel, a valveseating recess on said opposite side adapted to receive the end of said head, said channel affording parallel walls adapted to guide the head inward across said conduit into sealing relationship, the head forming with the walls of the channel a chamber for containing fluid, said head fitting at all times against said parallel walls to block any appreciable movement of fluid between said conduit and said chamber, said head having at least one distensible wall whereby the head may flt more firmly within said parallel surfaces and said recess, said head having a hollow space beneath said distensible wall whereby said fluid may exert a force against the distensible wall adapted to press the distensible wall more firmly against the surface of the channel means to periodically increase the amount of fluid in said chamber thereby eaiming corresponding inward strokes of the head to its innermost and seated position with a material increase of pressure in the fluid chamber after the head has reached its innermost position thus in turn causing a distension of said distensible wall to scaling position.

13. A closure assembly comprising a housing having a conduit therein, there being a channel in the housing intersecting with and extending to the opposite side of said conduit, a head adapted to slide in said channel, a valve-seating recess on said opposite side adapted to receive the end of said head, said channel affording parallel walls adapted to guide the head inward across said conduit into sealing relationship, a piston adapted to slide in the channel in its outside portion outside of said head, the head and piston forming with the parallel walls of the channel a chamber for containing fluid, said head acting at all times to block any appreciable movement of fluid between said conduit and said chamber, said head and piston being joined by linkage means permitting relative mevement between the head and the piston up to predetermined limit while resisting relative movement beyond said limit, said head having at least one distensible wall whereby the head may fit more firmly within said parallel surfaces and said recess, said head having a hollow space beneath said distensible wall whereby said fluid may exert a force against the distensible wall adapted to press the distensible wall firmly against the surface of the channel means to maintain a constant amount of fluid in said chamber whereby each successive inward stroke of the piston will cause a corresponding inward stroke of the head to its innermost and seated position with a material increase of pressure in the fluid chamber after the head has reached its innermost position thus in turn causing a distension of said distensible wall to sealing position, and means to periodically operate said piston.

14. A closure assembly comprising a housing having a conduit therein, there being a channel in the housing intersecting with and extending to the opposite side of said conduit, a head adapted to slide in said channel, a valve-seating recess on said opposite side adapted to receive the end of said head, said channel afior 'ng parallel walls adapted to guide the head inward across said conduit into sealing relationship, a piston adapted to slide in the channel in its outside portion outside of said head, the head and piston forming with the parallel walls of the channel for containing fluid, said head and piston being joined by a link member permitting relative movement between the head and the piston up to predetermined limit while resisting relative movement beyond said limit, said head having at least one distensible wall whereby the head may fit more firmly within said parallel surfaces and said recess, said head having a hollow space beneath said distensible wall whereby said fiuid may exert a force against the distensible wall adapted to press the distensible wall more firmly against the surface of the channel, whereby each inward stroke of the piston will cause a corresponding inward stroke of the head to its innermost and seated position with a material increase of pressure in thefluid chamber after the head has reached its innermost position, thus in turn causing a distension of said distensible wall to sealing position, means flowably connected to said chamber to displace an extra quantity of fluid into the chamber, means to operate the piston and said displacementmeans in chronological relationship so that said extra fluid is displaced into the chamber during the end part of the inward stroke of the head. I

15. A slide valve assembly comprising a hollow fluid-containing valve, a guide structure in which said valve is movable, said structure providing a guide extending into and interfitting with the open end of said hollow valve, said guide-afiording sealing surfaces cooperating with the inside surfaces of said valve, and means for actuating said valve to slide the same alonga path defined by said structure and for distending the valve at the end of its path.

' KENNETH H. MACKAY. 

